Life Before Birth - New Testament

There are a few places that teach us that we lived before we were born as taught in the Holy Bible. One of those places is an obscure reference:

As Jesus passed by, he saw a man which was blind from his birth. And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind? Jesus answered, Neither hath this man sinned, nor his parents. (John 9:1-3)

If life before birth did not exist then part of this scenario makes sense:

Master, ... did ... his parents [sin], that he was born blind? Jesus answered, ... his parents [hath not sinned that he was born blind].

I am confident that the apostles knew that God does not administer judgments or punishments before the offenses occur. It is reasonable to assume that they did not know if God would punish the parents through an affliction on their child. In this case at least, we know that this did not happen. However, if we omit this portion of the dialogue, we read it as follows:

Master, ... did ... this man [sin], ... that he was born blind? Jesus answered, ... this man [hath not] sinned [that he was born blind].

Again, we know that God does not administer judgments or punishments before the offenses occur. If He did He would be an unjust God. Then if blindness were a punishment for sin, something the apostles assumed at the time of the question, then we must also assume they believed that he may have sinned before he was born. If they believe that he may have sinned before he was born then they also believe that he lived before he was born. Therefore, the concept of life before birth existed in the New Testament as shown in these verses.